Problem: Solve for $x$ : $5\sqrt{x} - 1 = 2\sqrt{x} + 9$
Subtract $2\sqrt{x}$ from both sides: $(5\sqrt{x} - 1) - 2\sqrt{x} = (2\sqrt{x} + 9) - 2\sqrt{x}$ $3\sqrt{x} - 1 = 9$ Add $1$ to both sides: $(3\sqrt{x} - 1) + 1 = 9 + 1$ $3\sqrt{x} = 10$ Divide both sides by $3$ $\frac{3\sqrt{x}}{3} = \frac{10}{3}$ Simplify. $\sqrt{x} = \dfrac{10}{3}$ Square both sides. $\sqrt{x} \cdot \sqrt{x} = \dfrac{10}{3} \cdot \dfrac{10}{3}$ $x = \dfrac{100}{9}$